With the United States government now shorn of its top credit rating by Standard & Poor's, experts are increasingly worried that the American economy is headed back into recession, while Europe appears vulnerable to another shock.

The announcement that the rating agency had reduced the U.S. government's AAA rating for the first time in history came after days of punishing declines in the stock market, and has now cast a shadow over economic prospects in the months ahead. A recent stream of indicators has provoked concern that the economy could be headed for another recession, with the growth rate slowing considerably, unemployment stubbornly elevated and the stock market swooning. Some experts say the downgrade could be the final trigger, making credit more expensive and sowing broad unease.